This invention pertains to improvements in a drywall-trimming strip of a type extruded from a polymeric material, such as polyvinyl chloride, and having a central portion having a bullnose region and two lateral flanges, each being joined unitarily to the central portion by a stepped junction.
Conventionally, in the United States, a drywall panel has a thickness of 0.5 inch approximately or a thickness of 0.625 inch approximately. Heretofore, drywall-trimming strips of the type noted above have been used widely in residential and commercial buildings and have been available commercially from Trim-Tex, Inc. of Lincolnwood, Ill., and from other sources. Commonly, as known heretofore, the central portion of such a strip has a bullnose profile having an exterior radius of not less than 0.75 inch approximately, which radius continues to the stepped junction joining each of the lateral flanges to the central portion.
When a drywall-trimming strip, as described in the preceding paragraph, is fitted along an elongate corner defined by two drywall panels, which may be conveniently called a first panel and a second panel, so that each of the drywall panels is disposed against an interior surface of one of the lateral flanges, and so that the first panel approximately butts against the second panel, the second panel is required to be set back from a plane defined by an outer surface of the first panel, by a sufficient distance to avoid interference between the second panel and the bullnose portion of the drywall-trimming strip.
If the bullnose region of the central portion has an exterior radius of 0.750 inch approximately, if each stepped junction has a measurement of 0.095 inch approximately, as measured between the exterior surface of the bullnose portion and the interior surface of whichever of the lateral flanges is joined by said stepped junction, and if drywall-trimming strip has a thickness of 0.055 inch approximately, a sufficient distance for the second panel to be set back is 0.398 inch approximately, which does not allow the bullnose portion to be well supported by the second panel, against damage from exterior blows.
This invention provides a drywall-trimming strip of the type noted above, extruded from a polymeric material, such as polyvinyl chloride, and having a central portion having a bullnose region between two planar regions, which are novel in a drywall-trimming strip. As before, the drywall-trimming strip has two lateral flanges, each of which is joined unitarily to the central portion by a stepped junction. As before, each stepped junctions has a measurement of 0.095 inch approximately, as measured between a plane defined by the exterior surface of the bullnose portion and a plane defined by the interior surface of whichever of the lateral flanges is joined unitarily to the bullnose portion by said stepped junction. As before, the drywall-trimming strip has a thickness of 0.055 inch approximately, as measured between the exterior and interior surfaces of the bullnose portion and as measured between the exterior and interior surfaces of each of the lateral flanges.
This invention contemplates that, between the planar regions of the central portion, the bullnose region of the central portion has an exterior radius in a range between 0.200 inch approximately and 0.350 inch approximately and that each of the planar regions has a width of 0.217 inch approximately, as measured in a plane normal to an axis defined by the bullnose region. Thus, the drywall-trimming strip is adapted to fit along an elongate corner defined by a first drywall panel and a second drywall panel, so that each drywall panel is disposed against an interior surface of one of the lateral flanges and so that the first drywall panel is permitted to abut or to be closely spaced from the second drywall panel, without requiring the second drywall panel to be set back from a plane defined by an outer surface of the first drywall panel, by a distance larger than 0.091 inch approximately, so as to avoid interference between the second panel and the bullnose portion of the drywall-trimming strip.
This invention also provides a combination of a drywall-trimming strip, as described in the preceding paragraph, a first drywall panel, and a second drywall panel, each drywall panel having a thickness not less than 0.5 inch approximately. The first and second drywall panels define an elongate corner, along which the drywall-trimming strip is fitted, along which the first drywall panel abuts or is spaced closely from the second drywall panel, and along which the second drywall panel is set back from a plane defined by an outer surface of the first drywall panel, by a distance as small as 0.091 inch approximately, without interference between the second drywall panel and the bullnose portion of the drywall-trimming strip.
In the preceding summary of this invention, in the following description of a preferred embodiment of this invention, and in the accompanying claims, xe2x80x9capproximatelyxe2x80x9d means xc2x10.005 inch.